dot-request: --inbox, and xz compression past 400 KB

--inbox files into another inbox than dot: the path it posts to and the
namespace it signs in both follow it, so the key signs for that inbox only.
DOT_REQUEST_URL still overrides the whole URL for testing.

A signed request over 400 KB -- the inbox's limit on the wire -- now goes
xz -9e compressed with Content-Encoding: xz, which the inbox undoes before
checking anything; a smaller one goes as it is. --compress and --no-compress
override that either way. Compressing needs xz, so it joins the Brewfile;
without it a request that must be compressed is refused, never sent plain.

Checked against a local inbox: 148 KB sent plain, 740 KB compressed to 37 KB
and accepted, --no-compress over the limit refused with 413, --compress on a
small request accepted, a bad --inbox name refused before signing.

0 files changed, 0 insertions, 0 deletions